Information on the nature of the game as a determinant of behavior in the prisoner’s dilemma

Fifty male and 50 female Ss play ed single trials of six prisoner’s dilemma games (PDGs) in each of two experimental conditions (ECs). In EC1, Ss read a descriptive matrix prior to playing. In EC2, no descriptive matrix was presented. Within each EC, two forms of matrix were employed: (A) where strategies were explicitly labeled COOPERATION and COMPETITION and (B) where strategies were identified by letters only. No significant sex differences were found. Significant differences were found in competitive behavior: EC1A > EC1B and EC1A > EC2A. The findings indicate that increased information results in increased competition.